1. Field of the Invention
The present invention relates to a sputtering apparatus, and more particularly, to a sputtering apparatus and a method of driving the sputtering apparatus that are capable of achieving an optimum deposition.
2. Background of the Related Art
In general, a sputtering apparatus typically deposits a target material on a substrate by colliding ions accelerated in plasma with a target. As compared to a chemical vapor deposition (CVD) apparatus that performs processes at a high temperature, the sputtering apparatus is advantageous in performing a sputtering process where a thin film can be formed while a substrate is maintained at a low temperature of about 400° C. Such a sputtering apparatus has been widely utilized for a flat panel display device such as a liquid crystal display (LCD) device, an organic electroluminescence device, or the like because of its simple structure and formation of a deposition layer in a short period of time.
The conventional sputtering apparatus has a cathode connected to a target, which is provided in a chamber, and an anode connected to a substrate. When a predetermined voltage is applied between the cathode and the anode, electrons are bombarded with an inert gas and are thus ionized. When the ionized positive ions are accelerated toward the cathode target and collide with the target, a target material is sputtered from the target, thereby depositing the target material on the substrate to form a predetermined layer. The electrons are excited by bombarding neutral atoms to thereby generate plasma. The plasma is maintained when an external potential is maintained and electrons are continuously generated.
The sputtering apparatus may be classified into a cluster type and an in-line type. FIG. 1 is a schematic cross-sectional view illustrating a cluster type-sputtering apparatus according to the related art. As shown in FIG. 1, the related art cluster type sputtering apparatus includes a chamber 100 that serves to accommodate a substrate 110 transferred from the outside, a lifter 120 that is able to be placed upright to support the substrate 110, a target 130 including a target material to be deposited onto the substrate 110, and a mask 140 arranged in front of the target 130. Specifically, the substrate 110 is transferred horizontally into the chamber 100 and mounted on the lifter 120. Then, the lifter 120 carrying the substrate 110 is lifted upright in the chamber 100, and a sputtering process is thus performed. This sputtering apparatus is advantageous in that the degree to which the vacuum and temperature change is minimized because the lifter 120 constantly maintains the vacuum and certain temperature. Also, a gap of about 5 mm between the mask 140 and the substrate 110 within the chamber 100 can be maintained, thereby minimizing the deposition of the target material from the target 130 onto the lifter 120 supporting the substrate 110. However, such a cluster type sputtering apparatus cannot perform a deposition process for a large-sized substrate, which is greater than 2 m×2 m, due to the weight of equipment and an increase in pump capacity.
Recently, an in-line type sputtering apparatus has been increasingly utilized to perform the deposition process for large-sized substrates. FIG. 2A is a plan view schematically illustrating an in-line type sputtering apparatus according to the related art. FIG. 2B is a cross-sectional view schematically illustrating the in-line type sputtering apparatus within a chamber. As shown in FIGS. 2A and 2B, the related art in-line sputtering apparatus has a carrier 220 to transfer a substrate 210 into a chamber 200. Then, unlike the aforementioned cluster type lifter 120, the carrier 220 is not placed upright within the chamber 200, but is moved in a direction perpendicular to a mask 240 of the chamber 200 to transfer the substrate 210 to a region facing a target 230, thereby depositing a target material from the target 230 onto the substrate 210.
However, even though the related art in-line type sputtering apparatus is suitable for the deposition process on a large-sized substrate, it is difficult to adjust a gap between the substrate 210 and the mask 240 to be smaller than 10 mm, because the carrier 220 is moved vertically to transfer the substrate 210 to a region facing the target material 230. In other words, when the substrate 210 and the carrier 220 are moved vertically, they may be bent due to thermal deformation or the like, thereby causing a variation of an error range in uniformity of the substrate 210 and the carrier 220. If the carrier 220 and the substrate 210 are transferred to the region facing the target material 230 regardless of such a variation, the substrate 210 and the mask 240 may have a gap greater than 10 mm in one region and smaller than 10 mm in another region, and may even contact each other. In the event that the substrate 210 and the mask 240 contact each other, the substrate 210 may be scratched by the mask 240 and thus contaminated, or the substrate 210 may be damaged by a collision with the mask 240. Moreover, in the related art in-line sputtering apparatus, since the substrate 210 and the mask 240 have the gap as wide as approximately 10 mm, particles generated by a back sputtering contaminate the carrier 220.